Hello, My Friend Recently Got Hit In The Testicles, He

Hello, my friend recently got hit in the testicles, he is 16 and he was hit badly on Saturday by a hand striking his testicles, he feels one of his testicles is slightly swollen and he says it's hard to be, he says he has to tense his body to pee, any ideas what this could be, or is it just testicular trauma?